Magnetic moment of helium in Its S13 metastable state

Abstract

The ratio of the electronic gJ value of He in its 1s2s, S13 metastable state to the gJ of H in its ground state has been redetermined by the atomic beam magnetic resonance method using separated oscillating fields. At magnetic fields of about 540 and 575 gauss the transitions Δm=±1,±2 in He and (F,m)=(1,0)(1,-1) in H are observed at frequencies of approximately 1570 Mc/sec and 1140 Mc/sec, respectively. The natural line shapes for the separated oscillating fields method are obtained with spacings between the oscillating fields of both 4.2 cm and 2.2 cm. The experimental result is gJ(He,S13)gJ(H,S122)|exp=1-(23.3±0.8)×10-6, which agrees with an earlier measurement having an accuracy of 16 ppm, and also with the theoretical value gJ(He,S13)gJ(H,S122)|theor=1-(23.3±1.0)×10-6 obtained by Perl and Hughes, which was computed from the Breit equation for He with the addition of a term to represent the interaction of the anomalous spin magnetic moment of each electron with the external magnetic field. © 1958 The American Physical Society.